The present invention relates generally to plasma cutting systems and other high power output welding-type systems such as welding and induction heating systems and, more particularly, to a method and apparatus for automatically determining a consumable type when a consumable is disposed within an electrode holder of a welding-type system.
Plasma cutting is a process in which an electric arc is used to cut a workpiece. Plasma cutters typically include a power source, an air supply, and a torch. The torch or plasma torch is used to create and maintain the arc and plasma that perform the cutting. The plasma cutting power source receives an input voltage from a transmission power line or generator and provides an output voltage to a pair of output terminals, one of which is connected to an electrode and the other of which is connected to the workpiece.
The air supply is used with most plasma cutters to help start the arc, provide the plasma gas to the torch, and cool the torch. A movable or fixed electrode or consumable serves as a cathode and a fixed nozzle serves an anode. The air supply moves the electrode and as the electrode moves away from the nozzle, it opens the nozzle, and a plasma jet is created. The plasma jet causes the arc to transfer to the work piece, and thus initiates the cutting process. In other plasma cutting systems, a high frequency starter is used to initiate the cutting process.
Plasma cutting systems are typically used to effectuate the cutting and/or gouging of a workpiece. In this regard, the consumable that is used during the plasma cutting process must be one that is tailored for the specific process being implemented. That is, plasma cutting components are generally classified as either cutting or gouging components. Additionally, plasma cutting components, either cutting or gouging, are typically rated or designed for a specific amperage. Therefore, before carrying out the plasma cutting process, a user must ensure that the proper consumable type has been selected as well as ensuring that the selected consumable has an amperage rating appropriate for the particulars of the plasma cutting process to be carried out. If the plasma cutting process particulars and the consumable are not properly matched, damage to the plasma cutting torch or its components and/or a poor-cut quality may result.
To achieve better accuracy in matching the consumable with the selected or to-be-carried-out plasma cutting process, torches have been designed to have an output range where as consumable components have specific output amperage levels. The consumable set, or components of the consumable set, are designed to operate best at specific parameters of amperage and air pressure. However, if a consumable set is not used under the specific parameters, it may be damaged or cutting performance may be reduced. Often the operator may place the wrong components in the torch and damage them or have bad cutting performance. In this regard, a user or customer must carefully watch to see that the right components are used and that the power source output is set correctly. The difficulty in managing this process negatively affects purchasing costs, storage requirements, and maintenance costs.
It would therefore be desirable to design a method and apparatus that automatically detects the type of consumable connected to the plasma cutting torch and automatically adjust the operating parameters of the plasma cutting system to match the consumable connected to the torch.